Mr Holdener, I am glad you have come so far and are now able to do the research you love and share it with everyone. I've been reading, following your work in magazines, and buying a pile of your books for about 30 years now. A million thanks to you sir, for a mountain of REAL and unbiased data.
I lived out my dreams as a kid, reading about your tests and research. Had a dynojet 248 in house, built and tuned all kinds of V8's, turbo 4's and everything inbetween. It was a great time. Glad to see you making a good living at it😁 Good job Mr Holdener😁 One of my Heroes
The 76mm turbo was too big on the small turbo if you run an 80mm for a big turbo. You need to look at the pre/post compressor pressure ratios on each turbo and get them into their efficiency range in their compressor maps Should size sorta like this: - a larger turbine t4 67mm with 60mm gates and a t6 80mm big turbo. Drop intake duration & lift on the cam to get the turbos into their realistic efficeny PR's for this setup: Take for instance an T04r-derived 67mm and a s480 based 80mm: 67mm: 1.4-2.4 PR 80mm: 2.0-3.2 (Yes, they can be taken higher, but lets be realistic on total boost). which means on the low end: (if atmospheric is 14.5psaiA ish) Psi interstage (between turbos): ~14-15psiG (2.0pr) Manifold(after small turbo): 21psiG (1.5) - 33psiG (2.4). You need to monitor pressure between each stage and adjust the gates to hit the best PR for the desired overall boost. On compounds, boost is your friend, so you need to size the cam differently than on a single stage setup. Almost like a PD blower cam. Much smaller lift and shorter duration on the intake side
@@richardholdener1727 No, I didnt. I was just making suggestions to help with the educational process of your videos. If you watch my vids, a lot of what we do is just from stuff laying around so I get and appreciate your work. I was simply making suggestions that can be applied in the future to help.
@@richardholdener1727 I didn't miss the part about you doing this with parts lying around. But that doesn't change facts. These turbos are improperly sized and the piping is a disaster. So if you were doing a "here's what not to do on a compound setup", you knocked it out of the park. But a lot of us want to see it done right. You should take BoostForBreakfast 's comment to heart, as there was more useful information concerning properly sizing compounds in his comment, than in your compound video series. But I get it, you had this stuff lying around. 🤦♂️
@@dj4monie yea, not much discussion on my channel about stuff yet. I was referring to the 'budget' stuff that is on there. I need to put together more content - just been very busy with work. Gale is one of the kings in the diesel world - i follow a lot of his stuff.
In this configuration, that cooler is actually an aftercooler. It's after all the compressor stages. If it were mounted between the turbos, then it would be an intercooler.
You're absolutely right though. I have Motor Trend on Demand and You're absolutely right about Richard's channel. Engine Masters pales in comparison to Richard's...
I think what you did was pretty awesome Richard. it's something I've wanted to do for a while. Personal funds haven't been there even though I have just about everything gathered up to do such. I thought of this process about 4-5 years ago. The issue that I see with what you did was you built a very inefficient exhaust feed for the primary turbo and then downsized it going to the larger Turbo.(also two wastegates are not needed for a single system.like unless if it's a big boost Set up. A larger wastegate ex.60 mm for the primary side would give you a lot better control what the primary Turbo. Also would allow the volume necessitated to drive the secondary Turbo it would bring down the drive pressure a good bit. Because now the primary turbo going along for the ride since the secondary Turbo is really doing the work. Also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm the secondary side which would give you a lot better control with the secondary Turbo. And would allow the volume necessity to do drive secondary turbo it would bring down the drive pressure a good bit. Because now the primary turbos going along for the ride since the secondary turbo is really doing the work. also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm to the secondary turbocharger. You can stage the wastegate Springs differently between the primary and secondary Turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing a turbo properly for the application is also very critical. You can stage the wastegate Springs differently between the primary and secondary turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing the turbos properly for the application is also very critical. I would definitely have a smaller turbo than a 76 for the primary something long the lines like a board Warner S366 with a lager than usual exhaust hosing for such a small motor if you're really wanting it to come on violent like a PDS blower car.
I know a couple dudes asked about lower end torque but I think we’d love to see the results of a built 4.8 and see how far you can push it down in the rpm range like 2200 to 4500 which is where most street and towing get done
Generally when sized right it spools faster than the small turbo and makes the power of the big turbo. Plus the big turbo can use a much oversized turbine equivalent to what you'd size for an engine with the displacement the engine w/small turbo spits out. THAT is where sizing comes into play. If the large turbo is too small, it chokes the engine. Too large and it relies on the small turbo too long.
lapieces I think that makes sense in theory but demonstrating it is another deal. For a lot of guys sizing a turbo properly is still black magic, and going off anecdotal evidence is lucky at best. A lot of these motors are going into trucks, Richard and I have chatted about this a bit already. This is good conversation to have because there is a lot of doubt out there regarding towing with a turbo ls.. which from my research has been done with great success.
For illustration purposes it would be great to see a comparison between this and the S480 big turbo as just a single on the 4.8 (ie what happens when you run the big turbo only in a normal non-compound setup) :)
Great work, This is a very informative video. Compound turbo set ups are no easy feet and there is a lot of conflicting information and opinions on the internet (as always). I’m building a compound turbo 4 pot zetec on my channel and was led to believe you can run the main boost controlling wastegates in the manifold to atmosphere with the other bypassing the little turbo. Effectively controlling the overall boost pressure from both units and relieving the back pressure. I can’t wait to get mine up and running to start seeing first hand what works and what needs tweaking to get the most out of the set up.
You should do that quick spool valve with an open header into a twin scroll turbo, show us the back pressure and all that good info. And if it worth it for a big motor
Isnt the point of compound turbo for high pressure boost. Wouldnt a sequential turbo setup give you the same result in a better way? Still a very interesting subject, nice job.
The third wastegate and big turbo are the only things creating boost. The first turbo is being bypassed by the way you have it routed.. try eliminating the third wastegates and let the first 2 vent to atmosphere. That way the little turbo can work with the large turbo like it needs to..
You post so much great/useful content that is right to the point. This video is one of the most interesting for learning. I doubt I will ever be messing with compounds, my brain barely comprehends singles, but this was very interesting.
Tractor pullers have been doing compound turbos on diesels since the 1970's, at up to 3 stages and 240 psi boost. Then they started doing 2 stage compound turbo at up to 80 psi boost on diesels converted to run on methanol with spark ignition in the 1980's. Go to a tractor pull and look at these guys' engines and talk to them. They're pulling 4500 HP from International 466's, they must know something.
I'd really like to see a built bottom end that can handle all the benefits of a compound Turbo System. I'd like to see it make power like a motor twice its size. I really think you need another wastegate in between the small turbo and Big Turbo or bigger Gates. that way you can turn the spring pressure up on your small turbo to the same level as your big turbo or close to it. The 7 lb Springs are probably being blown open before that turbo even make 7 pounds... so you're not even getting the benefit of the small Turbo.
I would just love to see what the setup can actually do versus you holding it back and I do realize why you're holding it back... it needs a built bottom end that can handle it.
I believe the compound turbo systems and combo boost centrifugal plus turbo are probably designed around high altitude performance. Like airplanes. Where at sea level a single supercharger may make enough boogie but at 20,000 it doesn’t. I like the idea but I think the turbos are good enough now that big single or twins is probably going to yield the best results. Cool test though.
Kind of the wrong too for the job. Compounds are there to make bit low rpm and midrange power/torque. The response being fully lit by 4500 makes me think the compound is a bit of a moot point . Probably also needed some more wastegate before the high pressure turbine because the drivepressure across the high side turbine should be a lot closer to manifold pressure along with low pressure turbine being more equal to boost level between the low and high pressure turbo
The actual point of compound turbos is to use the small turbo to increase the effective displacement of the engine so that it will have the required exhaust energy to spool a very large turbo. I the Diesel World yes we use compound turbos to increase the mid range and low end torque/horsepower but this is just a side effect of what is actually going on.
@@compted10 no, thats the entire point of why you compound. turbo response at lower rpm. peak power will not change and in some cases increase running a large turbo or just the atmospheric turbo in this case alone. peak airflow is dicated by the larges compressor open to atmosphere
@@whatchu_talkin_john_willis no the point of the small turbo is to create the exhaust flow of a larger engine. The reason big turbos can make more power alone is back pressure control as well as the compressor cover restrictions.
@@compted10 no lol, that is the FUNCTION (IE how it works) not the objective (the goal you're trying to achieve) the objective is to increase engine power delivery responsiveness (IE quicker turbo response) and widen the usable powercurve.
Ill be around 12.5:1 compression in my audi a4 1.8t on e85 With compound turbos. Should make about 500awhp. I think high compression is the way to go if you have access to corn juice
Love the videos now! What was the back pressure before the small turbo at 21psi? Maybe you could do a video on crossover pipe size next. Since the internet engineers claim two inch pipe is all you need or you will kill velocity and spool time. Keep up the good work, you need your own show on motor trend.
Hey Dick, its one thing to survive a dyno pull, but keep an eye on the smaller turbo rpm, might only be blowing through it but rotation speed will chernobyl that wind pump of yours. Much love on your vids, we should link up.
Very good video. I'm very interested in how much torque could be produced from a 4.8 or 5.3 if the lower end was built. I'm always wishing I had more torque with the smaller LS.
It would be nice if there were forged internals. What good is a motor that wouldn't last 500 miles, not to mention to see how much power a compound set-up can make with a high reving short stoke engine. Thanks for the info that you bring us.
@@scottrussell2281 honestly it usually is the exact opposite of that. This would be the correct system, but he has all the wrong sizes between the turbos and the big turbo has to small of an exhaust.
The trick would be figuring out the pully ratio so that you don't max the procharger too early and get the big turbo to spool faster. Screw and paddle blowers work for this, but their lifespans are drastically shortened due to vein deflection from so much pressure on the inlet side. In the end we're asking components to do things they were never intended to do.
@@ARK842001 see the problem with a centrifugal supercharger paired with an even larger turbo is that they are both rising boost curves so they really wouldn't be that great until you got all the way to the top. Ask the Duramax guys who tried it. It in the end just kind of sucked.
If wg line of both turbos are on the same reference spot on the intake what will happen is this: Small turbo spools -> makes 7 psi and that psi opens all the wastegates including the big turbo wastegate. This way you as a result make 7psi on the small turbos and then you take them out of the equation aka you bypass them, and have that 7psi from the big turbo. Small turbo has its wategates wide open, air follows the less ressistance pass and all gases go through the wategates to the big turbo for it to make 7 psi. The thing that you can do this mean you have enough wastegate flow on the small turbo and thats perfect. The thing that you couldnt raise pressure on the big turbo is not because of back pressure its the opposite. Its because the combination of 2 things 1) pressure multiplies on compound turbos 2) wastegate reference point. If big turbo pressurises to 2 p.r (1bar) and that air goes to small turbo to be pressurised again to 2p.r. (1 bar) Final result wont be 1 bar + 1 bar = 2 bar. It will be 2pr x 2pr aka 4 times the atmospheric ressure AKA 4 bars of boost. What this means is that IF the small turbo receives pressurised air the final boost will be multiple times your small turbo wastegate and will open too quick. For your desired pressurisation. The trick is to put the big turbo wastegate line to the intermediate charge piping and then you have the staged compression result and boost controll. This way youll see how fast the boost raises because of the multipling effect. if you hook a boost gauge on the intermediate piping youll see that when the big turbo is sleeping you have vaccum or 0 bar reading. When the small turbo wastegate opens and you have enought exuast gases for the big turbo to be pressurised every 1 psi on the intermediate pipe will be 2 or more on your normal boost gauge. This way you compare final to intermediate pressure to find what % of the boost the small turbo creates. And then to controll boost accordingly.
The compound turbo made a believer out of me. Thought it was too complicated till I saw the low end boost numbers with the adjustment. Next time run it with 12psi down low. Want to see those numbers
I'm with the guy who wants to see lower rpm boost. The whole point of compounds is to get boost lower in the rpms. 4500 from an ls isn't that great. I bet with a properly sized small turbo that big charger will come on way earlier
we can make a lot more low speed torque by adjusting the controller for the small turbo-just didn't want the load in torque on the dyno-but you can have it on the street or track
Would like to see a jy 5.3 with a quality ring set pushed on low torque with this setup to see what the gen3 & gen4 rods and stock crank can handle. When these things start to let go
@@wheezin_the_juice the Gen 3 properly tuned in fueled will make an excess of 1000 crank horsepower then the rods will start to bend roughly about 1300 a 1400 horsepower on a Gen 4 then the rods break. The tuning the tuning the tuning the tuning the tune is extremely critical
an interstage bypass bleed may be a good idea. turbine engines with multiple compressor stages usually have them to control surge for different sections of compressor stages as the compressors come up on their maps differently and surge often requires a partial tear down or at a minimum a borescope inspection
If you ever find yourself with a smaller small turbo and a bigger big turbo just sitting around, I'd love to see what that sort of combination could do. Seems like it ought to be possible to get 15-20psi boost around 2k RPM from the little one, and 1000+whp at the top end from the big one, which would be delightful.
Mr. Holdener, nice test although I'm surprised at the high back pressure, I thought the two wastegates would have lowered that. I was looking around on RUclips and found DeBoss Garage did something similar but completely different. Lookup: Four diesel turbos on an LS and you will find theirs. You made a lot more peak power but their torque curve is glorious, in the LAST (when everything worked) run A lot to learn in both experiments.
I like the concept behind this but my only problem is with application. Unless you are building a rear engine setup or you're dropping this in a dump truck/18 wheeler, you can't mount this system in a race car or truck and have any visibility. Your system is great for proving the benefits of compound boost but needs work when it comes to fitment in everyday applications.
What about doing something on the Vortec 454/496 2001-2009. Would be interesting to see what kind of power you can get out of the stock bottom end, even though they are all iron motors.
Mr. Holdener, Diesel Power Source makes a VGT turbo in the S300 and S400 sizes. They say the turbine has a ratio spread from .48 to 1.10, it is controlled by the exhaust drive pressure. Have you ever tested a VGT Turbo?? Do you think Diesel Power Source would let you borrow one?? I'm sure they would, if it worked out they would make sales.
Richard what about sequential turbos rather than compounds . Same setup. Instead of running the s480s outlet into the 7665 inlet take both otlets And y them together.
I've always wondered what the power difference would be . If I were to do it I would use 2 throttle bodys on the outlets with out any springs making it so air can flow one way freely and if it try to flow back naturally it would close. Everything else I would keep the same. Pressure would work its self out look triple turbo diesels . I'll tell you what your 4.8 made more power than my 5.9 with s488 . Gotta love rpm and free flowing heads.
That's the sweetness of it. Sized properly with plenty of wastegate on the primary with a 30-35% larger secondary you can eliminate lag and get boost off launch without cooking the valves and turbine two stepping. Two step sucks for the turbo and the motor.
why not connect the primary turbo`s(small) wastgate reference signal to the exhaust manifold and the big turbo`s wastegate (the one actually controling ultimate engine boost)to the intake manifold and set the primary turbo`s wastegate spring pressure to the desired intake manifold boost.this way i think you would have balance between the turbos and maybe a 1:1 pressure differential in the exahust man and intake manifold provided the secondary exhaust housing doesn`t get restrictive?
well, in this case where one turbo is smaller than other, i would run with spool valve (or other type of TB in exhaust), so i get boost in low rpm, but still carry it to higher rpm with bigger turbo.. in your case to get smaller backpressure, i would put one more wastegate before 1st turbo and also use at least air-air intercooler as heatsink after 2nd turbo
i would love to see an update with this. maybe get more of that low end that you were talking about and see how early and flat you could get the horse power. as always great video. its also funny to watch your older stuff compared to what you put out now. you've gotten a lot better at editing. you should consider "remastering" some of your older content :)
I have been toying with this idea for a rotary engine for circuit use to gain torque down low but still have high boost levels at the rotary crazy rpm range but I can not figure out how to size the turbos properly. I do want to do a trick intake set up to play with those compounds as well.
Hey love your videos. Ideally you'd have one big wastegate before the small turbo that controls both banks, and vent it to atmosphere, that way you control both turbos at the same time, if you slow down the small turbo compared to the larger one you're losing the whole point of the compund setup, the slower the small turbo moves the less air it multiplies and the less exhaust that passes through the turbine because it's spinning slower.
Interesting from an academic perspective, but with modern turbo's there doesn't seem to be much value in a compound setup (for low boost applications.) That intake vs exhaust pressure difference is pretty bad and no doubt robbing a load of power. Would have been good to see what the power curve on just a single large turbo would have been. No doubt capable of supplying the required mass flow.
850hp???? Freaking insane! What kind of compression? I want to build a small block ford that can achieve this.. I have a 66 fastback I'm about to turn into a runner
The ONLY thing I dont like about compound turbo's iis reliability.. Too many extra variables that take effect. Compound supercharger/turbo setup seems much more reasonable, reliable and makes more sense in the grand scheme. The turbo driven off the exhaust and the supercharger driven off the engine, sounds like the combo!
I have a compound turbo Subaru outback. two holset diesel turbos. Been driving well over a year. I haven't added a wastegate between the two turbos yet. Getting some emaps setup soon.
This guy is me, with money. LOL. "Bro, what if we....." I'd be skipping thru aisles of my own racking, with a shopping cart, "this, and this, ooooooo you too, yup need this".
If that engine was installed into a heavy car like an old GM a body you would want a torque curve that starts early in the rpm range . Seems like that would involve adjusting the waste gates on the smaller primary turbo ?
How heavy is heavy? My olds with the 350 olds in it is 3740lbs? Plan on going single turbo on it. This compound setup looks good for the tow truck though
Great video Richard! Turbo boost is thought as free HP by using the waste exhaust of an engine. All forms of boost use crankshaft HP. You once mentioned of running a second engine, to supply the exhaust to feed a turbo(s), to determine the amount of crankshaft HP consumed by a turbo system. Did this experiment ever happen? Thank you, Tony
I have not but that would be cool-the turbo uses very little power-basically just the back pressure-much less than superchargers at the same boost level
I wonder if you could possibly get a close estimate if you ran the engine with turbo and measure the back pressure. Then run the engine N/A , then replicate the same amount of back pressure on the N/A engine that the turbo engine has. Of course the Hp would be lower so you would have use it as a percentage of Hp loss per. Excuse me if I made that sound confusing! lol but im interested to see also!
@@JohnnyAnderson1 you can see the effect of back pressure if we eliminate it with the right turbo, but its 20-30 hp compared to 200-300 hp at high boost with a supercharger
@@richardholdener1727 IMHO your estimated 20-30hp loss is a little conservative. I'm in agreement when you minimize the exhaust to intake pressure ratio, that hp will increase. However, exhaust back pressure is still a load on the engine, not the same load as a blower with all the rotational mass of the rotors, frictional losses and inefficiencies. Maybe in the order of 1/2 the hp loss of a belt driven blower?
How about two compound setups (4 turbos), one compound running off the left bank, and vice versa, going into dual 4 barrel.... With nitrous. And methanol... On e85
Hey Richard! Could you make a video about how to control boost and tune effectively. I feel like most people know how turbos work but don't know about wastegates, blow off valves, etc.
play with compound supercharger/turbo. OEM are going that way as opposed to compound turbo. in your setup, the engine sees that 23psi back pressure. An SC creates no back pressure and has instant throttle response. the S480 might even be too small for that setup.
Would this turbocharger set just be for trucks or heavy vehicles. How fast does this set spool up? Could the Holley set be used to set the boost control? What was the torque down low? Thanks
it would not be just for trucks-it could be used for any performance application, it spools up quick with the small turbo, Holley can run an electronic controller and you can adjust the torque output as indicated in the video
gathering what I have seen from a Methanol fueled 4 cylinder with compound turbos, you don't need an interstage blow off valve or bypass. the entire thing is plumbed in series so you mass flow will always be (air in + fuel == exhaust out - piston ring blow by) all of you control valving can be on the high pressure side IE on the small turbo. when you bleed off high pressure exhaust directly into the atmosphere your throwing away that mass and all the energy it carries AWAY from the turbine wheels.
Interesting results! Thank you for testing this stuff. I was wondering if you've ever messed around with the steam ports? A lot of guys say they just block them off but some say if you do you can cause hot spots in the cylinder heads? has any testing been done on this with multiple temp sensors and/or egt sensors?
Awesome video only one thing wouldn't it be better to have the small compressor feeding the larger turbo inducer and then going through the cooler to the motor so it helps to minimize lag for the large turbo but i have seen it done both ways
Ever think about trying a turbo from a Duramax with a variable vane tubo. Should create so big response. It be super fun to try and make that combo work. Gives u one more thing u can control to make controllable boost and response.
So what would happen with no wastegates on the smaller turbo. It does make sense to route some of that energy around the smaller turbo.i guess the smaller turbo would run away and create to much back pressure.
@@richardholdener1727 gotcha. So basically 2 smaller wastegates to control the smaller turbo and then a larger maybe a 60mm on the s480. I'm trying to create a twin compound setup so wondering how to make it possible
Got a test for you to do. How about a 4.8 compound turbo setup with twin ebay gt45’s as the “big” turbos”. Have no idea what size primary turbo to use so that’s up to you.
That was real interesting, some things I predicted to myself but some things surprised me a little, would like to see you do a compound positive blower/ turbo deal, I know LSA blowers are not as plentiful as 4.8 & 5.3 motors but how about it, LSA blower stock cam with big turbo then LS9 cam same combo then perf NA cam then blower cam then turbo cam, like to see pressure ratios and boost curves compared to compound turbo deal
I imagine this is mentioned below, but your high pressure turbos wastegate (the small turbo) doesn't have its "atmospheric" reference. You shouldnt reference the post IC line only, you need to connect to the mid charge pipe. The top of the gates is seeing dyno room pressure, not its inlet pressure. The delta of pressures makes this system work correctly. Would love to see this happen again with these updates!
Dear Richard... You may have the best "job" of any man....if you can call what you do work and not just having the timenof your life lol. Good work as usual👍
So aside from quickened boost response would this be any faster in a car at the same manifold boost pressure as a single correctly sized turbo. Very interesting, just wondering if there would be a reason to do this aside from a video like this.
Richard can you do an LS stroker engine with the fast 102mm intake and the new lsxhr tunnel ram? Would love to see the differences in the low and mid range and also the torque output. Use a good size cam.
There's a Buick Regal out there somewhere with this setup. There's one vid of a quick dyno hit, it's beyond ferocious. Look up "compound LS" till you see what looks like a GN, that's the one. There's very lil info on the internets, surprisingly, about it
I did a Holley cast set up vs tube and compared back pressure, but spool is hard to quantify on the engine dyno-it's an artificial load at the starting rpm
Can you swap the places of the turbos and put a t3/4 (~60mm) turbo instead of the 75mm after the larger frame turbo?(so 80mm feeding into the 60mm) I feel like by having the larger turbo first you might not run into as much back pressure before the first turbo? Having the large turbo feed into the smaller turbo, since it takes much more rpm to spool the large turbo having the small one after it. I don't think would affect spooling it that bad since its getting twice the amount of exhaust it would normally get even if its at a lower velocity? Wouldn't this give you low end power until the large frame turbo spools up and then max boost is based off the back pressure of the smaller turbo at the end? I dont know im only asking questions or do i have the position of the turbos backwards?
Have you ever tested a twin turbo setup with both the same size but 1 journal bearing and 1 ball bearing and run both journal only and ball bearing only to see what’s the difference and if having them different makes a difference?
Great recearch and a learning curve for all. Would like to see more boost at lower Rpm. More torque would be the ...result. Great video. Can you perhaps jack up the audio by using lap microphone... Will make the video much better
@@richardholdener1727 yea what he said on sound quality if u could figure out just how to keep the volume equalized. I know these aren't Spielberg produced but it's all constructive criticism lol. thanks man
![3000HP, 150 PSI Of Boost | What Do YOU Know About Compound Turbo Systems | Shane T [TECH TALK]](http://i.ytimg.com/vi/1pV_tLbZY0A/mqdefault.jpg)
I can tell you're passionate about your work...you're a lucky dude to be doing what you love.
...and it shows. Cheers man!
Mr Holdener, I am glad you have come so far and are now able to do the research you love and share it with everyone. I've been reading, following your work in magazines, and buying a pile of your books for about 30 years now. A million thanks to you sir, for a mountain of REAL and unbiased data.
Kyle Milligan happy there are Guys Out there who like dyno results as much as I do
I lived out my dreams as a kid, reading about your tests and research. Had a dynojet 248 in house, built and tuned all kinds of V8's, turbo 4's and everything inbetween. It was a great time. Glad to see you making a good living at it😁 Good job Mr Holdener😁 One of my Heroes
The 76mm turbo was too big on the small turbo if you run an 80mm for a big turbo. You need to look at the pre/post compressor pressure ratios on each turbo and get them into their efficiency range in their compressor maps
Should size sorta like this:
- a larger turbine t4 67mm with 60mm gates and a t6 80mm big turbo. Drop intake duration & lift on the cam to get the turbos into their realistic efficeny PR's for this setup:
Take for instance an T04r-derived 67mm and a s480 based 80mm:
67mm: 1.4-2.4 PR
80mm: 2.0-3.2
(Yes, they can be taken higher, but lets be realistic on total boost).
which means on the low end: (if atmospheric is 14.5psaiA ish)
Psi interstage (between turbos): ~14-15psiG (2.0pr)
Manifold(after small turbo): 21psiG (1.5) - 33psiG (2.4).
You need to monitor pressure between each stage and adjust the gates to hit the best PR for the desired overall boost. On compounds, boost is your friend, so you need to size the cam differently than on a single stage setup. Almost like a PD blower cam. Much smaller lift and shorter duration on the intake side
did you miss the part about these being the turbos I had laying around?
@@richardholdener1727 No, I didnt. I was just making suggestions to help with the educational process of your videos. If you watch my vids, a lot of what we do is just from stuff laying around so I get and appreciate your work.
I was simply making suggestions that can be applied in the future to help.
@@BoostForBreakfast thnx for the advice
@@richardholdener1727 I didn't miss the part about you doing this with parts lying around. But that doesn't change facts. These turbos are improperly sized and the piping is a disaster. So if you were doing a "here's what not to do on a compound setup", you knocked it out of the park. But a lot of us want to see it done right. You should take BoostForBreakfast
's comment to heart, as there was more useful information concerning properly sizing compounds in his comment, than in your compound video series.
But I get it, you had this stuff lying around. 🤦♂️
@@dj4monie yea, not much discussion on my channel about stuff yet. I was referring to the 'budget' stuff that is on there. I need to put together more content - just been very busy with work. Gale is one of the kings in the diesel world - i follow a lot of his stuff.
Love the longer video with the in depth analysis. Something about a compound setup just sounds mesmerizing, almost demonic 👍🏻
I want to see one with a supercharger - best of both worlds!
P
I like the idea of all the brains u put in it pretty much cool
In this configuration, that cooler is actually an aftercooler. It's after all the compressor stages. If it were mounted between the turbos, then it would be an intercooler.
Your like Engine Masters on steroids. good job Richard. I'm enjoying your content.
Dick-Terd...sorry man, I have a friend named Richard, and that's what I've always called him. I'll go sit in the corner now...🤣 🤣 🤣
You're absolutely right though. I have Motor Trend on Demand and You're absolutely right about Richard's channel. Engine Masters pales in comparison to Richard's...
I think what you did was pretty awesome Richard. it's something I've wanted to do for a while. Personal funds haven't been there even though I have just about everything gathered up to do such. I thought of this process about 4-5 years ago. The issue that I see with what you did was you built a very inefficient exhaust feed for the primary turbo and then downsized it going to the larger Turbo.(also two wastegates are not needed for a single system.like unless if it's a big boost Set up. A larger wastegate ex.60 mm for the primary side would give you a lot better control what the primary Turbo. Also would allow the volume necessitated to drive the secondary Turbo it would bring down the drive pressure a good bit. Because now the primary turbo going along for the ride since the secondary Turbo is really doing the work. Also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm the secondary side which would give you a lot better control with the secondary Turbo. And would allow the volume necessity to do drive secondary turbo it would bring down the drive pressure a good bit. Because now the primary turbos going along for the ride since the secondary turbo is really doing the work. also with the secondary turbo since you have so much energy coming out from the primary turbo plus the wastegate bypass you need to run a larger gate example 66 mm to the secondary turbocharger. You can stage the wastegate Springs differently between the primary and secondary Turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing a turbo properly for the application is also very critical. You can stage the wastegate Springs differently between the primary and secondary turbo no problem and if you can figure it properly you can control it all on one boost controller. Plus sizing the turbos properly for the application is also very critical. I would definitely have a smaller turbo than a 76 for the primary something long the lines like a board Warner S366 with a lager than usual exhaust hosing for such a small motor if you're really wanting it to come on violent like a PDS blower car.
I know a couple dudes asked about lower end torque but I think we’d love to see the results of a built 4.8 and see how far you can push it down in the rpm range like 2200 to 4500 which is where most street and towing get done
Generally when sized right it spools faster than the small turbo and makes the power of the big turbo. Plus the big turbo can use a much oversized turbine equivalent to what you'd size for an engine with the displacement the engine w/small turbo spits out.
THAT is where sizing comes into play. If the large turbo is too small, it chokes the engine. Too large and it relies on the small turbo too long.
That's the purpose of compound turbo, to spool faster. Besides 8 cylinders will spool a single turbo pretty well
lapieces I think that makes sense in theory but demonstrating it is another deal. For a lot of guys sizing a turbo properly is still black magic, and going off anecdotal evidence is lucky at best. A lot of these motors are going into trucks, Richard and I have chatted about this a bit already. This is good conversation to have because there is a lot of doubt out there regarding towing with a turbo ls.. which from my research has been done with great success.
Hydrocarbon82 fully agree, and my comment below touches on that a bit.
For illustration purposes it would be great to see a comparison between this and the S480 big turbo as just a single on the 4.8 (ie what happens when you run the big turbo only in a normal non-compound setup)
:)
I have it vs an S475 I ran on this motor
@@richardholdener1727 new to the channel so may have missed it :)
colonelk3000 no worries my friend -the results of the s475 aren’t up-you are the only one that knows I ran it-so shssssh-don’t tell any one
@@richardholdener1727 I seen the comment. The secret is out hahaha
Results the same, just power comes on later in the powerband
love the longer detailed format man. Glad you got to play and we were entertained
Thnx-should be like this going forward!
Great work, This is a very informative video. Compound turbo set ups are no easy feet and there is a lot of conflicting information and opinions on the internet (as always). I’m building a compound turbo 4 pot zetec on my channel and was led to believe you can run the main boost controlling wastegates in the manifold to atmosphere with the other bypassing the little turbo. Effectively controlling the overall boost pressure from both units and relieving the back pressure. I can’t wait to get mine up and running to start seeing first hand what works and what needs tweaking to get the most out of the set up.
You should do that quick spool valve with an open header into a twin scroll turbo, show us the back pressure and all that good info. And if it worth it for a big motor
Isnt the point of compound turbo for high pressure boost.
Wouldnt a sequential turbo setup give you the same result in a better way?
Still a very interesting subject, nice job.
Sequential might be a better choice for an LS-just harder to plumb
Double the pressure, double the fun. Don't forget lower egt with Compound turbos.
The third wastegate and big turbo are the only things creating boost. The first turbo is being bypassed by the way you have it routed.. try eliminating the third wastegates and let the first 2 vent to atmosphere. That way the little turbo can work with the large turbo like it needs to..
THAT DIDN'T WORK
You post so much great/useful content that is right to the point. This video is one of the most interesting for learning. I doubt I will ever be messing with compounds, my brain barely comprehends singles, but this was very interesting.
2nd time I'm watching this series, appreciate the knowledge you've given us!
Tractor pullers have been doing compound turbos on diesels since the 1970's, at up to 3 stages and 240 psi boost. Then they started doing 2 stage compound turbo at up to 80 psi boost on diesels converted to run on methanol with spark ignition in the 1980's. Go to a tractor pull and look at these guys' engines and talk to them. They're pulling 4500 HP from International 466's, they must know something.
I'd really like to see a built bottom end that can handle all the benefits of a compound Turbo System. I'd like to see it make power like a motor twice its size. I really think you need another wastegate in between the small turbo and Big Turbo or bigger Gates. that way you can turn the spring pressure up on your small turbo to the same level as your big turbo or close to it. The 7 lb Springs are probably being blown open before that turbo even make 7 pounds... so you're not even getting the benefit of the small Turbo.
all the boost as indicated-we can raise the boost up on the small turbo as much as desired-we just didn’t want the load-in torque
I would just love to see what the setup can actually do versus you holding it back and I do realize why you're holding it back... it needs a built bottom end that can handle it.
Very interesting setup - thank you. Better audio would make a huge difference in the overall video quality.
I believe the compound turbo systems and combo boost centrifugal plus turbo are probably designed around high altitude performance. Like airplanes. Where at sea level a single supercharger may make enough boogie but at 20,000 it doesn’t. I like the idea but I think the turbos are good enough now that big single or twins is probably going to yield the best results. Cool test though.
Kind of the wrong too for the job. Compounds are there to make bit low rpm and midrange power/torque. The response being fully lit by 4500 makes me think the compound is a bit of a moot point . Probably also needed some more wastegate before the high pressure turbine because the drivepressure across the high side turbine should be a lot closer to manifold pressure along with low pressure turbine being more equal to boost level between the low and high pressure turbo
The actual point of compound turbos is to use the small turbo to increase the effective displacement of the engine so that it will have the required exhaust energy to spool a very large turbo. I the Diesel World yes we use compound turbos to increase the mid range and low end torque/horsepower but this is just a side effect of what is actually going on.
@@compted10 no, thats the entire point of why you compound. turbo response at lower rpm. peak power will not change and in some cases increase running a large turbo or just the atmospheric turbo in this case alone. peak airflow is dicated by the larges compressor open to atmosphere
@@whatchu_talkin_john_willis no the point of the small turbo is to create the exhaust flow of a larger engine. The reason big turbos can make more power alone is back pressure control as well as the compressor cover restrictions.
@@compted10 no lol, that is the FUNCTION (IE how it works) not the objective (the goal you're trying to achieve) the objective is to increase engine power delivery responsiveness (IE quicker turbo response) and widen the usable powercurve.
@@whatchu_talkin_john_willis I think we are arguing the same point from both ends.
😼Hey Richard, when you get done with compound turbos. Do a boosted engine with 12.5:1 compression. With whatever fuel it takes.
S rage that works
Ill be around 12.5:1 compression in my audi a4 1.8t on e85 With compound turbos. Should make about 500awhp. I think high compression is the way to go if you have access to corn juice
I'd love to see an optimized compound setup, with intercoolers after each stage, on proper built motor.
I'm not sure mine is properly built or optimized, but 1200 hp on a 2 liter 4 cylinder with ice water intercooling for each stage works very well.
Love the videos now! What was the back pressure before the small turbo at 21psi? Maybe you could do a video on crossover pipe size next. Since the internet engineers claim two inch pipe is all you need or you will kill velocity and spool time. Keep up the good work, you need your own show on motor trend.
Richard I thought the hole compound turbo was made for getting a "flat line" HP and torque wise, so you dont loose power in the rev range?
Hey Dick, its one thing to survive a dyno pull, but keep an eye on the smaller turbo rpm, might only be blowing through it but rotation speed will chernobyl that wind pump of yours.
Much love on your vids, we should link up.
Very good video. I'm very interested in how much torque could be produced from a 4.8 or 5.3 if the lower end was built. I'm always wishing I had more torque with the smaller LS.
I'm sure that most everyone would really like to see how tunable/possible output. I've been thinking alot about this set-up myself. Thanks
It would be nice if there were forged internals. What good is a motor that wouldn't last 500 miles, not to mention to see how much power a compound set-up can make with a high reving short stoke engine. Thanks for the info that you bring us.
I would like to see a compound setup with a procharger style blower and a turbo!
I'd love to see this as well. Seems like a perfect "have your cake and eat it too" scenario.
@@scottrussell2281 honestly it usually is the exact opposite of that. This would be the correct system, but he has all the wrong sizes between the turbos and the big turbo has to small of an exhaust.
What we need to see is an lsa blower with a turbo
The trick would be figuring out the pully ratio so that you don't max the procharger too early and get the big turbo to spool faster. Screw and paddle blowers work for this, but their lifespans are drastically shortened due to vein deflection from so much pressure on the inlet side. In the end we're asking components to do things they were never intended to do.
@@ARK842001 see the problem with a centrifugal supercharger paired with an even larger turbo is that they are both rising boost curves so they really wouldn't be that great until you got all the way to the top. Ask the Duramax guys who tried it. It in the end just kind of sucked.
If wg line of both turbos are on the same reference spot on the intake what will happen is this:
Small turbo spools -> makes 7 psi and that psi opens all the wastegates including the big turbo wastegate.
This way you as a result make 7psi on the small turbos and then you take them out of the equation aka you bypass them, and have that 7psi from the big turbo. Small turbo has its wategates wide open, air follows the less ressistance pass and all gases go through the wategates to the big turbo for it to make 7 psi. The thing that you can do this mean you have enough wastegate flow on the small turbo and thats perfect.
The thing that you couldnt raise pressure on the big turbo is not because of back pressure its the opposite. Its because the combination of 2 things 1) pressure multiplies on compound turbos 2) wastegate reference point.
If big turbo pressurises to 2 p.r (1bar) and that air goes to small turbo to be pressurised again to 2p.r. (1 bar)
Final result wont be 1 bar + 1 bar = 2 bar. It will be 2pr x 2pr aka 4 times the atmospheric ressure AKA 4 bars of boost. What this means is that IF the small turbo receives pressurised air the final boost will be multiple times your small turbo wastegate and will open too quick. For your desired pressurisation. The trick is to put the big turbo wastegate line to the intermediate charge piping and then you have the staged compression result and boost controll.
This way youll see how fast the boost raises because of the multipling effect. if you hook a boost gauge on the intermediate piping youll see that when the big turbo is sleeping you have vaccum or 0 bar reading. When the small turbo wastegate opens and you have enought exuast gases for the big turbo to be pressurised every 1 psi on the intermediate pipe will be 2 or more on your normal boost gauge.
This way you compare final to intermediate pressure to find what % of the boost the small turbo creates.
And then to controll boost accordingly.
The compound turbo made a believer out of me. Thought it was too complicated till I saw the low end boost numbers with the adjustment. Next time run it with 12psi down low. Want to see those numbers
I'm with the guy who wants to see lower rpm boost. The whole point of compounds is to get boost lower in the rpms. 4500 from an ls isn't that great. I bet with a properly sized small turbo that big charger will come on way earlier
we can make a lot more low speed torque by adjusting the controller for the small turbo-just didn't want the load in torque on the dyno-but you can have it on the street or track
Would like to see a jy 5.3 with a quality ring set pushed on low torque with this setup to see what the gen3 & gen4 rods and stock crank can handle. When these things start to let go
You're the guy who loves detonation...
@@justinbryant237 Or maybe he knows how to tune.
@@wheezin_the_juice the Gen 3 properly tuned in fueled will make an excess of 1000 crank horsepower then the rods will start to bend roughly about 1300 a 1400 horsepower on a Gen 4 then the rods break. The tuning the tuning the tuning the tuning the tune is extremely critical
an interstage bypass bleed may be a good idea. turbine engines with multiple compressor stages usually have them to control surge for different sections of compressor stages as the compressors come up on their maps differently and surge often requires a partial tear down or at a minimum a borescope inspection
If you ever find yourself with a smaller small turbo and a bigger big turbo just sitting around, I'd love to see what that sort of combination could do. Seems like it ought to be possible to get 15-20psi boost around 2k RPM from the little one, and 1000+whp at the top end from the big one, which would be delightful.
this combination of turbos will do that-we just didn't want that much torque on the load in
I pressed “ like” times🤣🤣🤣. Thank you for doing experiments we would never dare do.
I think the atmospheric turbo needs to be larger both the turbine and compressor side to move more air at a lower pressure ratio.
Mr. Holdener, nice test although I'm surprised at the high back pressure, I thought the two wastegates would have lowered that.
I was looking around on RUclips and found DeBoss Garage did something similar but completely different.
Lookup: Four diesel turbos on an LS and you will find theirs. You made a lot more peak power but their torque curve is glorious, in the LAST (when everything worked) run
A lot to learn in both experiments.
as explained, there was a reason we didn't add more torque down low but it is certainly possible
@@richardholdener1727 When I said the torque curve was glorious I'm referring to how long and flat it was, not the amount.
@@johnparrish9215 no worries, you can shape the curve nicely with dual controllers on a compound
And love your videos! Keep em coming! I'm learning a lot!
Thanks , very interesting vid . I’m glad you fixed the 4.8 lt and got it all working ! Looking forward to the next vid !
I like the concept behind this but my only problem is with application. Unless you are building a rear engine setup or you're dropping this in a dump truck/18 wheeler, you can't mount this system in a race car or truck and have any visibility. Your system is great for proving the benefits of compound boost but needs work when it comes to fitment in everyday applications.
it only had to fit the dyno-we would plumb differently for a specific chassis
What about doing something on the Vortec 454/496 2001-2009. Would be interesting to see what kind of power you can get out of the stock bottom end, even though they are all iron motors.
William Moody I would love to but not much support for them
Bro you do everything rite even if it is wrong your the one testing and doing this for all of us I dont see anyone else doing what you do
Mr. Holdener, Diesel Power Source makes a VGT turbo in the S300 and S400 sizes. They say the turbine has a ratio spread from .48 to 1.10, it is controlled by the exhaust drive pressure.
Have you ever tested a VGT Turbo??
Do you think Diesel Power Source would let you borrow one?? I'm sure they would, if it worked out they would make sales.
i have not tried one
Richard what about sequential turbos rather than compounds . Same setup. Instead of running the s480s outlet into the 7665 inlet take both otlets And y them together.
Sequential is cool but hard to get the switch over and requires a lot of tubing and valves
I've always wondered what the power difference would be .
If I were to do it I would use 2 throttle bodys on the outlets with out any springs making it so air can flow one way freely and if it try to flow back naturally it would close. Everything else I would keep the same. Pressure would work its self out look triple turbo diesels .
I'll tell you what your 4.8 made more power than my 5.9 with s488 . Gotta love rpm and free flowing heads.
That's the sweetness of it. Sized properly with plenty of wastegate on the primary with a 30-35% larger secondary you can eliminate lag and get boost off launch without cooking the valves and turbine two stepping. Two step sucks for the turbo and the motor.
why not connect the primary turbo`s(small) wastgate reference signal to the exhaust manifold and the big turbo`s wastegate (the one actually controling ultimate engine boost)to the intake manifold and set the primary turbo`s wastegate spring pressure to the desired intake manifold boost.this way i think you would have balance between the turbos and maybe a 1:1 pressure differential in the exahust man and intake manifold provided the secondary exhaust housing doesn`t get restrictive?
I should be receiving my compound setup short block from the machine shop next week. 🤙
well, in this case where one turbo is smaller than other, i would run with spool valve (or other type of TB in exhaust), so i get boost in low rpm, but still carry it to higher rpm with bigger turbo..
in your case to get smaller backpressure, i would put one more wastegate before 1st turbo and also use at least air-air intercooler as heatsink after 2nd turbo
Pretty cool. Those stock rods and pistons do not liked to be clubbed over the head at low rpm. Richard what was the timing at low rpm?
in the teens-13-14
i would love to see an update with this. maybe get more of that low end that you were talking about and see how early and flat you could get the horse power. as always great video. its also funny to watch your older stuff compared to what you put out now. you've gotten a lot better at editing. you should consider "remastering" some of your older content :)
With a a setup like this im looking for : Higher low end power/ longer high end torque/ and continuous shift boost.
I have been toying with this idea for a rotary engine for circuit use to gain torque down low but still have high boost levels at the rotary crazy rpm range but I can not figure out how to size the turbos properly. I do want to do a trick intake set up to play with those compounds as well.
Hey love your videos. Ideally you'd have one big wastegate before the small turbo that controls both banks, and vent it to atmosphere, that way you control both turbos at the same time, if you slow down the small turbo compared to the larger one you're losing the whole point of the compund setup, the slower the small turbo moves the less air it multiplies and the less exhaust that passes through the turbine because it's spinning slower.
Interesting from an academic perspective, but with modern turbo's there doesn't seem to be much value in a compound setup (for low boost applications.) That intake vs exhaust pressure difference is pretty bad and no doubt robbing a load of power.
Would have been good to see what the power curve on just a single large turbo would have been. No doubt capable of supplying the required mass flow.
850hp???? Freaking insane! What kind of compression? I want to build a small block ford that can achieve this.. I have a 66 fastback I'm about to turn into a runner
Love the grassroots breakdown, beats the big corp shows
The ONLY thing I dont like about compound turbo's iis reliability.. Too many extra variables that take effect. Compound supercharger/turbo setup seems much more reasonable, reliable and makes more sense in the grand scheme. The turbo driven off the exhaust and the supercharger driven off the engine, sounds like the combo!
neither is really necessary on a LS
Can you try a compound turbo setup on a GM series 2 3800 v6 or GM 4200 inline 6 since there are plenty of them in the junkyard.
Ridiculously good tech here Richard, thank you!!
Thank you for watching
I have a compound turbo Subaru outback. two holset diesel turbos. Been driving well over a year. I haven't added a wastegate between the two turbos yet. Getting some emaps setup soon.
This guy is me, with money. LOL. "Bro, what if we....." I'd be skipping thru aisles of my own racking, with a shopping cart, "this, and this, ooooooo you too, yup need this".
If that engine was installed into a heavy car like an old GM a body you would want a torque curve that starts early in the rpm range . Seems like that would involve adjusting the waste gates on the smaller primary turbo ?
yep-that's easy to do, I just stopped adding boost and torque down low but there was a lot left
How heavy is heavy? My olds with the 350 olds in it is 3740lbs? Plan on going single turbo on it. This compound setup looks good for the tow truck though
Great video Richard! Turbo boost is thought as free HP by using the waste exhaust of an engine. All forms of boost use crankshaft HP. You once mentioned of running a second engine, to supply the exhaust to feed a turbo(s), to determine the amount of crankshaft HP consumed by a turbo system. Did this experiment ever happen? Thank you, Tony
I have not but that would be cool-the turbo uses very little power-basically just the back pressure-much less than superchargers at the same boost level
I wonder if you could possibly get a close estimate if you ran the engine with turbo and measure the back pressure. Then run the engine N/A , then replicate the same amount of back pressure on the N/A engine that the turbo engine has. Of course the Hp would be lower so you would have use it as a percentage of Hp loss per.
Excuse me if I made that sound confusing! lol but im interested to see also!
@@JohnnyAnderson1 you can see the effect of back pressure if we eliminate it with the right turbo, but its 20-30 hp compared to 200-300 hp at high boost with a supercharger
😂😂
@@richardholdener1727 IMHO your estimated 20-30hp loss is a little conservative. I'm in agreement when you minimize the exhaust to intake pressure ratio, that hp will increase. However, exhaust back pressure is still a load on the engine, not the same load as a blower with all the rotational mass of the rotors, frictional losses and inefficiencies. Maybe in the order of 1/2 the hp loss of a belt driven blower?
How about two compound setups (4 turbos), one compound running off the left bank, and vice versa, going into dual 4 barrel.... With nitrous. And methanol... On e85
Hey Richard! Could you make a video about how to control boost and tune effectively. I feel like most people know how turbos work but don't know about wastegates, blow off valves, etc.
+1
play with compound supercharger/turbo. OEM are going that way as opposed to compound turbo. in your setup, the engine sees that 23psi back pressure. An SC creates no back pressure and has instant throttle response. the S480 might even be too small for that setup.
Would this turbocharger set just be for trucks or heavy vehicles. How fast does this set spool up? Could the Holley set be used to set the boost control? What was the torque down low?
Thanks
it would not be just for trucks-it could be used for any performance application, it spools up quick with the small turbo, Holley can run an electronic controller and you can adjust the torque output as indicated in the video
gathering what I have seen from a Methanol fueled 4 cylinder with compound turbos, you don't need an interstage blow off valve or bypass. the entire thing is plumbed in series so you mass flow will always be (air in + fuel == exhaust out - piston ring blow by) all of you control valving can be on the high pressure side IE on the small turbo. when you bleed off high pressure exhaust directly into the atmosphere your throwing away that mass and all the energy it carries AWAY from the turbine wheels.
Its recirculated into the large turbos turbine. It's way to big of a setup but besides that mostly plumbed correctly
I agree though, Bov is not needed except 2 of them near the throttle body. Wastegate is correct however.
Interesting results! Thank you for testing this stuff. I was wondering if you've ever messed around with the steam ports? A lot of guys say they just block them off but some say if you do you can cause hot spots in the cylinder heads? has any testing been done on this with multiple temp sensors and/or egt sensors?
we usually don't run them on the dyno but have not tested them with sensors are you described
Yet another very informative video. Glad to see you love your work (play).
Keep up the great videos.
Love that braille welding!
You need have the small turbo feeding the big turbo. Then have the big turbo feed the engine.
A pair of properly sized 61s would have made 1050 horsepower at 7000 RPMs. Looks like the gain is in low-end torque which will bend rods
Let's push the gen3 & gen4 rods to see what they can handle down low. We've seen they can handle a ton in the upper range 👌🏽👍🏽🤘🏽
Rob Nordo I wanna know too lol!
849 HP is nasty on a compound setup. IDK why people dont often do it since it is very efficient
Awesome video only one thing wouldn't it be better to have the small compressor feeding the larger turbo inducer and then going through the cooler to the motor so it helps to minimize lag for the large turbo but i have seen it done both ways
My favorite part if this is trying to picture the engine bay that this fits into...
Looks like you didn't really need the 3rd waste gate. But maybe bigger gates for the other 2
Ever think about trying a turbo from a Duramax with a variable vane tubo. Should create so big response. It be super fun to try and make that combo work. Gives u one more thing u can control to make controllable boost and response.
So what would happen with no wastegates on the smaller turbo. It does make sense to route some of that energy around the smaller turbo.i guess the smaller turbo would run away and create to much back pressure.
boost would get very high at low engine speeds-not good!
@@richardholdener1727 gotcha. So basically 2 smaller wastegates to control the smaller turbo and then a larger maybe a 60mm on the s480. I'm trying to create a twin compound setup so wondering how to make it possible
Got a test for you to do. How about a 4.8 compound turbo setup with twin ebay gt45’s as the “big” turbos”. Have no idea what size primary turbo to use so that’s up to you.
That was real interesting, some things I predicted to myself but some things surprised me a little, would like to see you do a compound positive blower/ turbo deal, I know LSA blowers are not as plentiful as 4.8 & 5.3 motors but how about it, LSA blower stock cam with big turbo then LS9 cam same combo then perf NA cam then blower cam then turbo cam, like to see pressure ratios and boost curves compared to compound turbo deal
Are you trying to sign? Or what is that spastic flailing suposed to be?
I'd have tried to get that small turbo to light up at lower rpm... it's probably too large.
I imagine this is mentioned below, but your high pressure turbos wastegate (the small turbo) doesn't have its "atmospheric" reference. You shouldnt reference the post IC line only, you need to connect to the mid charge pipe. The top of the gates is seeing dyno room pressure, not its inlet pressure. The delta of pressures makes this system work correctly. Would love to see this happen again with these updates!
Dear Richard... You may have the best "job" of any man....if you can call what you do work and not just having the timenof your life lol. Good work as usual👍
So aside from quickened boost response would this be any faster in a car at the same manifold boost pressure as a single correctly sized turbo. Very interesting, just wondering if there would be a reason to do this aside from a video like this.
Richard can you do an LS stroker engine with the fast 102mm intake and the new lsxhr tunnel ram?
Would love to see the differences in the low and mid range and also the torque output.
Use a good size cam.
I haven't run the new fast but have run the Carbon version
@@richardholdener1727 where is that video?
I’m extremely curious how a twin charges setup would change the equation.
compound turbo and blower?
Yes sir. I can honestly say I’ve never seen a twin charged LS set up.
There's a Buick Regal out there somewhere with this setup. There's one vid of a quick dyno hit, it's beyond ferocious. Look up "compound LS" till you see what looks like a GN, that's the one. There's very lil info on the internets, surprisingly, about it
Can you compare a log manifold vs a custom setup? See which one spools quicker, has better heat control etc?
I did a Holley cast set up vs tube and compared back pressure, but spool is hard to quantify on the engine dyno-it's an artificial load at the starting rpm
I want to see a compound Turbo on a hellcat long block thru a holley intake.
BW s280 and s400 make a killer combination on a 6.0.
Can you swap the places of the turbos and put a t3/4 (~60mm) turbo instead of the 75mm after the larger frame turbo?(so 80mm feeding into the 60mm) I feel like by having the larger turbo first you might not run into as much back pressure before the first turbo? Having the large turbo feed into the smaller turbo, since it takes much more rpm to spool the large turbo having the small one after it. I don't think would affect spooling it that bad since its getting twice the amount of exhaust it would normally get even if its at a lower velocity? Wouldn't this give you low end power until the large frame turbo spools up and then max boost is based off the back pressure of the smaller turbo at the end? I dont know im only asking questions or do i have the position of the turbos backwards?
the exhaust is routed to the small turbo first
Lots of info to digest.
Looks like you put alot of work into this one. 👍
It was a lot of building, fixing the motor, testing and editing, but that's how we learn and have fun.
Have you ever tested a twin turbo setup with both the same size but 1 journal bearing and 1 ball bearing and run both journal only and ball bearing only to see what’s the difference and if having them different makes a difference?
the difference between journal and ball bearing is mostly longevity and not spool rate or power
I know very little, but aren't you suppose to compound the smaller turbo ( which boosts faster) to the larger turbo to spool it faster? Cool set up.
Great recearch and a learning curve for all. Would like to see more boost at lower Rpm. More torque would be the ...result. Great video. Can you perhaps jack up the audio by using lap microphone... Will make the video much better
I used a lav mic on this one but can turn up the volume
@@richardholdener1727 Thanks a mil. Your videos are awesome. I learn so much, and you do the hard work. LS Rox!!!
@@thysellis3677 happy to help
@@richardholdener1727 yea what he said on sound quality if u could figure out just how to keep the volume equalized.
I know these aren't Spielberg produced but it's all constructive criticism lol. thanks man
Can you do this again but with a intercooler and a aftercooler
I’d like to see a gen1 billet 78/75 with a S496 on the 4.8L with some good good valve train chugging up to the moon around 8300-8400rpm.
It doesn't need to run to 8,300 to max that turbo out, but it would sound good
Talk with Gale Banks on this Turbo set up. I'm almost certain you can crack 1000 horsepower reliable threw Gale's information.